diff options
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 70 |
1 files changed, 59 insertions, 11 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 8ea117f8142e..fb4302738410 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -25,6 +25,7 @@ #include <asm/geode.h> #include <asm/apic.h> #include <asm/intel-family.h> +#include <asm/i8259.h> unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */ EXPORT_SYMBOL(cpu_khz); @@ -363,6 +364,20 @@ static unsigned long pit_calibrate_tsc(u32 latch, unsigned long ms, int loopmin) unsigned long tscmin, tscmax; int pitcnt; + if (!has_legacy_pic()) { + /* + * Relies on tsc_early_delay_calibrate() to have given us semi + * usable udelay(), wait for the same 50ms we would have with + * the PIT loop below. + */ + udelay(10 * USEC_PER_MSEC); + udelay(10 * USEC_PER_MSEC); + udelay(10 * USEC_PER_MSEC); + udelay(10 * USEC_PER_MSEC); + udelay(10 * USEC_PER_MSEC); + return ULONG_MAX; + } + /* Set the Gate high, disable speaker */ outb((inb(0x61) & ~0x02) | 0x01, 0x61); @@ -487,6 +502,9 @@ static unsigned long quick_pit_calibrate(void) u64 tsc, delta; unsigned long d1, d2; + if (!has_legacy_pic()) + return 0; + /* Set the Gate high, disable speaker */ outb((inb(0x61) & ~0x02) | 0x01, 0x61); @@ -602,7 +620,6 @@ unsigned long native_calibrate_tsc(void) case INTEL_FAM6_KABYLAKE_DESKTOP: crystal_khz = 24000; /* 24.0 MHz */ break; - case INTEL_FAM6_SKYLAKE_X: case INTEL_FAM6_ATOM_DENVERTON: crystal_khz = 25000; /* 25.0 MHz */ break; @@ -612,6 +629,8 @@ unsigned long native_calibrate_tsc(void) } } + if (crystal_khz == 0) + return 0; /* * TSC frequency determined by CPUID is a "hardware reported" * frequency and is the most accurate one so far we have. This @@ -987,8 +1006,6 @@ static void __init detect_art(void) /* clocksource code */ -static struct clocksource clocksource_tsc; - static void tsc_resume(struct clocksource *cs) { tsc_verify_tsc_adjust(true); @@ -1039,12 +1056,31 @@ static void tsc_cs_tick_stable(struct clocksource *cs) /* * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc() */ +static struct clocksource clocksource_tsc_early = { + .name = "tsc-early", + .rating = 299, + .read = read_tsc, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS | + CLOCK_SOURCE_MUST_VERIFY, + .archdata = { .vclock_mode = VCLOCK_TSC }, + .resume = tsc_resume, + .mark_unstable = tsc_cs_mark_unstable, + .tick_stable = tsc_cs_tick_stable, +}; + +/* + * Must mark VALID_FOR_HRES early such that when we unregister tsc_early + * this one will immediately take over. We will only register if TSC has + * been found good. + */ static struct clocksource clocksource_tsc = { .name = "tsc", .rating = 300, .read = read_tsc, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | + CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_MUST_VERIFY, .archdata = { .vclock_mode = VCLOCK_TSC }, .resume = tsc_resume, @@ -1168,8 +1204,8 @@ static void tsc_refine_calibration_work(struct work_struct *work) int cpu; /* Don't bother refining TSC on unstable systems */ - if (check_tsc_unstable()) - goto out; + if (tsc_unstable) + return; /* * Since the work is started early in boot, we may be @@ -1221,9 +1257,13 @@ static void tsc_refine_calibration_work(struct work_struct *work) set_cyc2ns_scale(tsc_khz, cpu, tsc_stop); out: + if (tsc_unstable) + return; + if (boot_cpu_has(X86_FEATURE_ART)) art_related_clocksource = &clocksource_tsc; clocksource_register_khz(&clocksource_tsc, tsc_khz); + clocksource_unregister(&clocksource_tsc_early); } @@ -1232,13 +1272,11 @@ static int __init init_tsc_clocksource(void) if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz) return 0; + if (check_tsc_unstable()) + return 0; + if (tsc_clocksource_reliable) clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY; - /* lower the rating if we already know its unstable: */ - if (check_tsc_unstable()) { - clocksource_tsc.rating = 0; - clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS; - } if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3)) clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP; @@ -1251,6 +1289,7 @@ static int __init init_tsc_clocksource(void) if (boot_cpu_has(X86_FEATURE_ART)) art_related_clocksource = &clocksource_tsc; clocksource_register_khz(&clocksource_tsc, tsc_khz); + clocksource_unregister(&clocksource_tsc_early); return 0; } @@ -1315,6 +1354,12 @@ void __init tsc_init(void) (unsigned long)cpu_khz / 1000, (unsigned long)cpu_khz % 1000); + if (cpu_khz != tsc_khz) { + pr_info("Detected %lu.%03lu MHz TSC", + (unsigned long)tsc_khz / 1000, + (unsigned long)tsc_khz % 1000); + } + /* Sanitize TSC ADJUST before cyc2ns gets initialized */ tsc_store_and_check_tsc_adjust(true); @@ -1349,9 +1394,12 @@ void __init tsc_init(void) check_system_tsc_reliable(); - if (unsynchronized_tsc()) + if (unsynchronized_tsc()) { mark_tsc_unstable("TSCs unsynchronized"); + return; + } + clocksource_register_khz(&clocksource_tsc_early, tsc_khz); detect_art(); } |